Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-0482; Project Identifier MCAI-2024-00152-T]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Notice of proposed rulemaking (NPRM). <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA proposes to supersede Airworthiness Directive (AD) 2019-16-09, which applies to certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. AD 2019-16-09 requires one-time inspections for cracks and damage of the elevator power control unit (PCU) brackets and surrounding area, horizontal stabilizer rear spar, and elevator front spar, and related investigative and corrective actions if necessary. Since the FAA issued AD 2019-16-09, new findings have been reported as a result of maintenance activities and/or inspections. This proposed AD would continue to require certain actions in AD 2019-16-09, and would also require repeating the inspections one time and performing applicable on-condition actions, remove an airplane from the applicability, and provide optional terminating action for the repetitive inspections. The FAA is proposing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> The FAA must receive comments on this proposed AD by August 7, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: • <E T="03">Federal eRulemaking Portal:</E> Go to <E T="03">regulations.gov</E> . Follow the instructions for submitting comments. • <E T="03">Fax:</E> 202-493-2251. • <E T="03">Mail:</E> U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. • <E T="03">Hand Delivery:</E> Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0482; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above. <E T="03">Material Incorporated by Reference:</E> • For Transport Canada material identified in this proposed AD, contact Transport Canada, Transport Canada National Aircraft Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-663-3639; email <E T="03">TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca</E> . You may find this material on the Transport Canada website at <E T="03">tc.canada.ca/en/aviation.</E> It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0482. • You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Yaser Osman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email <E T="03">9-avs-nyaco-cos@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Comments Invited</HD> The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the <E T="02">ADDRESSES</E> section. Include “Docket No. FAA-2025-0482; Project Identifier MCAI-2024-00152-T” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments. Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to <E T="03">regulations.gov</E> , including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. <HD SOURCE="HD1">Confidential Business Information</HD> CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Yaser Osman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email <E T="03">9-avs-nyaco-cos@faa.gov.</E> Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. <HD SOURCE="HD1">Background</HD> The FAA issued AD 2019-16-09, Amendment 39-19712 (84 FR 46434, September 4, 2019) (AD 2019-16-09), for certain De Havilland Aircraft of Canada Limited Model DHC-8-400, -401, and -402 airplanes. AD 2019-16-09 was prompted by an MCAI originated by Transport Canada, which is the aviation authority for Canada. Transport Canada issued AD CF-2018-34, dated December 17, 2018 (Transport Canada AD CF-2018-34), to correct an unsafe condition. AD 2019-16-09 requires one-time inspections for cracks and damage of the elevator PCU fittings (brackets) and surrounding area, horizontal stabilizer rear spar, and elevator front spar, and related investigative and corrective actions if necessary. The FAA issued AD 2019-16-09 to address failure of an elevator PCU fitting (bracket) or fracture of the front spar into two segments; either structural failure may cause a jam in one elevator or a loss of airplane pitch control if both elevators are affected. <HD SOURCE="HD1">Actions Since AD 2019-16-09 Was Issued</HD> Since the FAA issued AD 2019-16-09, Transport Canada superseded AD CF-2018-34 and issued Transport Canada AD CF-2024-10, dated March 1, 2024 (Transport Canada AD CF-2024-10), to correct an unsafe condition for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. Transport Canada AD CF-2024-10 states that new findings have been reported as a result of maintenance activities and/or inspections performed in accordance with De Havilland Aircraft of Canada Limited Service Bulletin 84-55-09, dated June 7, 2018 (the service information required by FAA AD 2019-16-09). Transport Canada AD CF-2024-10 requires repeating the inspections one time and performing applicable on-condition actions, while maintaining the requirements of AD 2019-16-09. Transport Canada AD CF-2024-10 also removes the requirement to report findings to the manufacturer. Transport Canada also issued AD CF-2025-19, dated March 24, 2025 (Transport Canada AD CF-2025-19), which provides a new design solution to address the unsafe condition identified in this NPRM and terminates the actions specified in Transport Canada AD CF-2024-10. The FAA is proposing this AD to address the unsafe condition on these products. You may examine Transport Canada ADs CF-2024-10 and CF-2025-19 in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0482. <HD SOURCE="HD1">Explanation of Retained Requirements</HD> Although this proposed AD does not explicitly restate the requirements of AD 2019-16-09, this proposed AD would retain certain requirements of AD 2019-16-09. Those requirements are referenced in Transport Canada AD CF-2024-10, which, in turn, is referenced in paragraph (g) of this proposed AD. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> Transport Canada AD CF-2024-10 specifies procedures for performing detailed visual and fluorescent penetrant inspections for cracks and damage of the elevator PCU fittings (brackets), horizontal stabilizer rear spar, and elevator front spar; repeating the inspections one time; rectifying any cracked or damaged elevator PCU fitting (bracket) (which includes replacing the elevator PCU fitting (bracket) and performing related investigative and corrective actions including performing an eddy current inspection for cracking of certain mating holes of the horizontal stabilizer rear spar); and repairing any cracked or damaged horizontal stabilizer rear spar assembly. Transport Canada AD CF-2025-19 specifies procedures for, among other actions, replacement of existing PCU fittings with redesigned PCU fittings. The replacement includes detailed inspections for damage and eddy current inspections for cracking, repair, installation of new bushings, and installation of doublers. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the <E T="02">ADDRESSES</E> section. <HD SOURCE="HD ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 25k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━